In the past, many different methods of interconnecting wiring boards have been developed. They have all tended to be complex and expensive but they provided an acceptable controlled radio frequency impedance transmission line for the then existing level of technology. Thus, there have been few new developments in this art.
In the past, there have been connectors such as those developed by G. A. Fedde, U.S. Pat. No. 3,221,286, granted Nov. 30, 1965. In this patent there are actually four separate boards involved which requires the connector to be a series of controlled impedance transmission lines, called strip lines, each on its own base. Each end of the connector is clamped between two of the boards and the impedance and transmission characteristics of the connector are controlled by adjusting the thickness of the connector base material. This invention provides no radio frequency shielding between the various wiring boards and is cumbersome and costly to implement.
Another type of connector was disclosed by C. B. May, U.S. Pat. No. 3,218,585, granted Nov. 16, 1965. The May patent shows a complex machined piece which in effect places a transmission line between two dielectrics in order to effectively form a waveguide between two parallel wiring boards. Essentially, six closely machined pieces are required to provide both the carrier of the strip conductor as well as the clamping mechanism for clamping the strip between the two wiring boards plus a closely toleranced dielectric material to carry the flat strip conductor. All this contributes to a very expensive connector.
In most other situations in the prior art, the attempt has been made to connect a strip line to a coaxial line which means to connect to another strip line requires a second similar coaxial line to strip line connector. All this adds cost. An example of this is shown by H. E. Lovejoy, U.S. Pat. No. 3,155,930, granted Nov. 3, 1964 and a simpler device is disclosed by C. B. May et al., U.S. Pat. No. 3,201,722, granted Aug. 17, 1965. This approach has also been used by the assignee of the present invention.
With these prior art connectors, the wiring boards are not easily connected and disconnected for installation and servicing purposes.
Heretofore, the best connector between controlled impedance transmission lines has been that developed and used by the assignee of the present invention and described as Prior Art. To allow appreciation of this Prior Art, it is discussed infra. in the Description of the Preferred Embodiment.